High-clearance agricultural vehicle

ABSTRACT

A high-clearance agricultural vehicle of the type used generally for spraying and otherwise treating row crops which grow to considerable height comprising a main frame extending longitudinally from the front to the rear of the upper portion of the vehicle, a pair of rear drive wheels disposed on opposite sides of and connected to the rear portion of the frame, a tank suspended from the frame to be disposed laterally between the rear wheels, a front wheel connected to the forward portion of the frame to be pivotally movable about a steering axis, an engine supported under the frame to be forwardly of the tank and behind the front wheel, and a transmission and axle assembly drivingly connecting the engine to the rear wheels. The main frame is defined by a pair of laterally spaced apart, longitudinally extending side members as the primary structural members. These members are formed to provide, above the engine, a cockpit for the operator of the vehicle, the rear portions of the members being laterally spaced apart by a distance approximately equal to the width of the tank. Each rear wheel is journal mounted by means of a yoke which is laterally adjustable relative to the frame. The engine is liquid cooled, and the radiator for the engine is disposed above the engine and in front of the cockpit in the frame. The fan associated with the radiator draws cooling air in from the side panels adjacent the engine and upwardly through the radiator and out through a grillwork in front of the radiator.

United States Patent [191 Sorenson et al.

[ HIGH-CLEARANCE AGRICULTURAL VEHICLE [75] Inventors: Charles E.Sorenson; Jon M.

Grimmer, both of Evansville, Ind.

[73] Assignee: Hahn, lnc., Evansville, Ind.

[22] Filed: May 26, 1972 [21] Appl. No.: 257,137

[58] Field of Search... 180/27, 1 F, 54 A, 68 R, 180/69 R, 72, 25 R, 26R, 89 R; 280/32.5, '280/106, 34 R [56] References Cited UNITED STATESPATENTS 2,985,379 5/1961 Strickland 239/172 1,681,426 8/1928 Nichols180/27 3,438,454 4/1969 Rickel et al.... 180/27 2,504,403 4/1950 Finley180/1 F 2,048,959 7/1936 Thompson 180/68 R 3,217,823 11/1965 Balthes r180/27 3,154,164 10/1964 Shaw et a1 280/34 R Primary Examiner-DavidSchonberg Assistant Examiner-John P. Silverstrim Attorney, Agent, orFirm-Hood & Coffey [57] ABSTRACT A high-clearance agricultural vehicleof the type used Jan. 29, 1974 generally for spraying and otherwisetreating row crops which grow to considerable height comprising a mainframe extending longitudinally from the front to the rear of the upperportion of the vehicle, a pair of rear drive wheels disposed on oppositesides of and connected to the rear portion of the frame, a tanksuspended from the frame to be disposed laterally between the rearwheels, a front wheel connected to the forward portion of the frame tobe pivotally movable about a steering axis, an engine supported underthe frame to be forwardly of the tank and behind the front wheel, and atransmission and axle assembly drivingly connecting the engine to therear wheels. The main frame is defined by a pair of laterallyspacedapart, longitudinally extending side members as the primary structuralmembers. These members are formed to provide, above the engine, acockpit for the operator of the vehicle, the rear portions of themembers being laterally spaced apart by a distance approximately equalto the width of the tank. Each rear wheel is journal mounted by means ofa yoke which is laterally adjustable relative to the frame. The engineis liquid cooled, and the radiator for the engine is disposed above theengine and in front of the cockpit in the frame, The fan associated withthe radiator draws cooling air in from the side panels adjacent theengine and upwardly through the radiator and out through a grillwork infront of the radiator.

12 Claims, 4 Drawing Figures mam 4m: 2 9 2974 3.788416 SHEU 1 BF 3 1HIGH-CLEARANCE AGRICULTURAL VEHICLE It is an object of the presentinvention to provide a high-clearance agricultural vehicle, the mainframe of which is formed with an enlargement providing a cockpit for theoperator of the vehicle, the cockpit being disposed above the engine.The engine is preferably liquid cooled, and the radiator for cooling theengine is disposed above the engine and forwardly of the cockpit. Thetwo rear wheels are journal mounted by yokes which are selectivelylaterally adjustable relative to the frame. j

High-clearance agricultural vehicles for use in spraying or otherwisetreating row crops which grow high have been in use for many years. Thedesign and development and use of these vehicles presents many problemswhich heretofore have not been satisfactorily solved. The main frame ofthe vehicle must be extremely high and quite narrow, and the necessaryequipment, such as the tank, must be disposed below the main frame andconfined to the width of the main frame to pass between the rows of acrop. Such vehicles have generally included two rear wheels and acentrally located front wheel, the rear wheels being supported by meanslaterally spaced from the main frame so that a row of crop can passbetween the tank supported below the main frame and each wheel.

Conventionally, the main frame has been provided by a pair of laterallyspaced apart, longitudinally extending parallel pipe members as theprimary structural members of the main frame. The support structure forthe engine, tank, wheel supports, and the like, have been welded tothese pipe members. Because of the narrow widthrequirements, it has beennecessary to provide a position for the'operator of the vehicle abovethe main frame. This places the operator in a position where he does nothave a satisfactory feeling of control and stability.-

The present invention is an improvement over the prior art devicesbecause the main frame is provided with an enlargement in its forwardportion providing a cockpit for the operator of the vehicle. Thisenlargement is located and proportioned and designed so that it willmove through tall row crops without damaging them. The enlargement forthe cockpit is disposed above the engine which provides a considerableportion of the mass of the vehicle. The placement of the cockpit withinthe frame lowers the center of gravity of the vehicle and gives theoperator greater feeling of control and stability. The cockpit disposedin this man- 2 a trunnion supported by the flanges journal mounting thewheel.

The engine of the vehicle of the present invention is preferably liquidcooled, and the radiator for cooling the engine is placed well above theengine and forwardly of the cockpit of the vehicle. Enclosure means 7 issuspended from the forward portion of the main frame to enclose theengine, this enclosure means providing ventilation openings at each sideadjacent the engine. A fan is disposed adjacent the radiator to draw airthrough the ventilation openings and upwardly through the radiator andforce it out through the front of the vehicle. One object of thepresentinvention is to keep the radiator in a position such that it isdisposed upwardly and away from the dirt and debris generated at thelower levels and particularly the dirt and debris kicked up by movementof the front wheel. By drawing the cooling air from the side walls ofthe enclosure for the engine and forcing it upwardly and out through thefront of the vehicle, the heat'of the engine compartment is drawn awayfrom the cockpit area where the operator resides.

Other objects and features of the present invention will become apparentas this description progresses.

To the accomplishment of the above and related objects, this inventionmay be embodied in the form illustrated in the accompanying drawings,attention being 1 called to the fact, however, that the drawings areillusner protects the operator by keeping him as low as possible.

The main frame of the vehicle of the present invention is preferablyformed from a pair of inwardly facing channel members instead of theusual pipe and gusset frame members. The weight to strength ratio ofthetrative only and that change may be made in the specific constructionillustrated and described, so long as the scope of the appended claimsis not violated.

In the drawings:

FIG. 1 is a perspective view of the vehicle of the present invention;

FIG. 2 is a top view of the main frame assembly of the vehicle of thepresent invention;

FIG. 3 is a fragmentary and partially cut away elevation view of thevehicle of the present invention; and

FIG. 4 is a fragmentary perspective view, partially cut away, of a reardrive wheel and the manner in which it is mounted for selectivelylateral adjustment on the vehicle.

Referring now to the drawings, it will be seen that the vehicle,indicated generally by the reference numeral 10, comprises a pair ofrear drive wheels, only one wheel 12 being shown, and a front wheel 16.The front wheel 16 is centrally located at the front of the vehicle 10,and the two rear wheels are laterally spaced apart from the rear portionof the vehicle.

The vehicle 10 comprises a main frame 22 extending longitudinally fromthe front to the rear of the upper portion of the vehicle, the mainframe having a rear portion 24, intermediate portion 26 and forwardportion 28. From the drawings, it will be appreciated that the mainframe 22 is defined by a pair of laterally spaced apart, longitudinallyextending side members 7 30, 32 as the primary structural members, theseside ber 30, 32 is allochirally related to the other channel member.

Further, from FIG. 2, itwill be seen that the portions 42 of the'channelmembers 30, 32 defining the rear portion 24 of the frame 22 aregenerally parallel and spaced apart bya first distance, the portions 44of the said members defining the intermediate portion 26 are inclininglaterally outwardly and forwardly, and the portions 46 of the saidmembers defining the forward portion 28 are generally parallel andspaced apart a second and greater distance to provide a cockpit 48 forthe operator therebetween.

Of course, the two channel members 30, 32 are rigidly connected togetherby cross plates and cross members such as the front cross plate 50,middle cross plate 52 and rear cross plate 54. Further, the two channelmembers are rigidly secured together by the means 60 for mounting eachrear 'wheel, the means including a pipe formed to extend across theframe 22 to provide front support arms 62 and another'such pipe formedto extend'across the frame to provide the rear support arms 64. Each armextends outwardly and downwardly from the rear portion 24 asillustrated. A mounting bracket or plate 66 is welded or otherwiserigidly secured to the distal ends of thearms 62, 64.

Each rear wheel is journal mounted by means of a yoke 70 formed toprovide a yoke base 72 and downwardly extending, laterally spaced apartvertical flanges 74, 76 on opposite sides of the wheel. A trunnion 78 ismounted on the lower ends of these flanges 74, 76 by means indicated at80 to journal mount the wheel therebetween; As clearly'shown in FIG. 4,a splined axle 88 extends laterally outwardly from the frame 22. Thedistal end of this axle 88 is journal mounted by means of a bearingmount 89 rigidly supported by the arms 62, 64. The axle 88 is drivinglyconnected to the its sprocket 91 are laterally adjustable by shiftingthe yoke 70 relative to the arms 62, 64. Particularly, the bracket plate66 provides a downwardly facing horizontally extending surface-and theyoke 70 base provides an upwardly facing, horizontally extending surfacein engagement with the downwardly facing surface. The length and widthof these surfaces are sufficient to provide a stable secure connectionof the yoke 70 to the bracket plate 66. In the illustrative embodiment,the bracket plate 66 is provided with laterally elongated slots 94 andthe yoke 70 base is provided with registering laterally elongated slots95. The yoke is secured to the bracket plate 66 by means of bolts 96which extend through these slots-Lateral adjustment of the yoke toaccommodate different row widths is 'accomplished by loosening the bolts96 and shifting the yoke laterally to the desired position and thentightening the bolts. The amount of adjustment, of course, is determinedby the length of the slots 94, 95. Of course, the lateral position ofthe sprocket 9.0 is adjusted on the axle 88 so that .it is in perfectalignment with the sprocket .91. A take-up idler sprocket such asindicated 4 at 100 may be used for providing the proper tension on thechain 92.

It will be appreciated that, in the illustrative and preferredembodiment, a yoke 106 provides a trunnion support for the front wheel16. A steering column indicated generally at 108 connects the yoke 106to the forward portion of the main frame 22 for pivotal movement about asteering axis lying generally in the said center plane of the vehicle,i.e., the vertical plane represented by the center line 38 in FIG. 2.Above the frame 22 and in front ofthe cockpit 48 is a steering controlbox 110 from which the steering wheel 112 is supported. Contained insidethis control box 110 is a conventional and commercially availablehydraulic control system for a power steering mechanism including ahydraulic cylinder for moving the steering column about its axis tosteer the front wheel 16.

conventionally, such vehicles 10 carry a large tank for storing liquidmaterial to be sprayed upon crops. Such a tank is suspended from therear portion 24 of the main frame 22 with the tank having a lateralwidth generally equal to the said first distance, i.e., the width of therear portion 24. The tank 120 is preferably generally U-shaped inlongitudinal cross section with its upwardly extending side walls beingsecured, at their upper edges, respectively to the outside surfaces ofthe portions 42 of the channel members 30, 32.

As best seen in FIG. 3, an engine 122 is mounted below the forwardportion 28 of the main frame 22 by frame members, such as indicated at124 connected to the frame 22. Preferably, the engine 122 is aliquidcooled reciprocating engine. of the type including a crankshaft,and the rotational axis of the crankshaft is preferably parallel to andclosely adjacent to or lying in said center plane of the vehicle. Atransmission 128 is disposed generally within the confines of the mainframe 22 just to the rear of the intermediate portion 26. Thistransmission 128 is drivingly connected to the engine 122 by belt means130 trained about pulley means 132 on the rear output shaft of theengine and pulley means 134 on the forwardly extending input shaft ofthe transmission 128. A drive shaft 136 drivingly connects thetransmission 128 to a rear axle assembly 138 which provides the splinedaxle ends 88 discussed in conjunction with FIG. 4.

An output shaft 142 for the engine 122 is illustrated in FIG. 3. Thisshaft 142 may be mounted on the crankshaft or drivingly connected to thecrankshaft of the engine. A conventional fan 144 may be journal mountedon the upper portion of the engine by conventional means such as theillustrated Water pump 145. This fan 144 is drivingly connected to theoutput shaft 142 by a belt 146 trained about a pulley 148 on the outputshaft and another pulley 150 on the fan 144.

A radiator for cooling the engine 122 is mounted ina chamber disposedabove the engine 122 and front wheel 16 and in front of the cockpit 48and steering column 108. Behind this radiator 160 is journal mounted aconventional automotive fan 162. This fan 162 is drivingly connected tothe output shaft 142 by a jack shaft 164 journal mounted for rotation inthe vehicle and extending from the upper portion of the enginecompartment to the said radiator chamber. A belt 166 is trained about apulley 169 on the output shaft 142 and another pulley 170 on the rearend of the shaft 164 to drive the shaft. Another belt 176 is trainedabout a pulley 178 on the forward end of the jack shaft Y 164 and apulley 180 on the fan 162 to drive the fan 162 from the jack shaft. Thejack shaft 164 is preferably parallel to the said center plane of thevehicle and laterally spaced apart therefrom to pass the steering column108.

The vehicle of the present invention comprises means for enclosing theengine compartment and the radiator chamber with the enclosure meansbeing formed such that it will move through the higher crops withoutdamaging them. The enclosure means depends from the enlarged forwardportion 28 of the main frame 22 to enclose the engine 122, the enclosuremeans including opposing side wall means having upper side panels 196covering the channel portions 46, upper side portions 192 extendingdownwardly from the channel portions 46 to a point above the engine, andlower side portions 194 extending respectively downwardly from the upperside portions 192 to a point below the engine. An engine compartmentfloor plate, not shown, extends between the lower edges of the lowerportion to close the compartment. The lateral distance between the lowerside portions 194 is generally equal to the said first distance, i.e.,the width of the tank 120, so that the enclosure means will pass betweenthe crop rows. In the illustrative and preferred embodiment, the upperportions 192 incline downwardly and inwardly from the portions 46 of thechannel members 30, 32 defining the forward portion 28 to the upperedges, respectively, of the lower side portions.

The side wall means of the enclosure extend forwardly of the steeringcolumn 108 to provide, above the front wheel 16 and forwardly of thecockpit 48, the said radiator chamber which is in communication with theportion of the enclosure means enclosing the'engine 122. The front wallmeans of this radiator chamber may be a screen-type grill such asindicated at 206 so that air moving through the radiator can passtherethrough. Adjacent the engine, the wall portions 194 are providedwith openings closed by doors 208 providing screen-type grills so thatair can circulate therethrough.

In the illustrative and preferred embodiment, the fan 162 is driven toforce air forwardly out through the radiator and the front of theradiator chamber. This fan draws air in through the ventilation openingsin the side doors 208. i

The movement of the enlargement in the frame 22 providing the cockpit 48through the crops is facilitated by panels such as indicated at 198 inFIG. 1 which incline forwardly and inwardly from the panels 196 to thefront panel 199; triangular panels such as indicated at 200 in FIG. 1which incline forwardly, inwardly and upwardly from the upper sideportions 192 to the front panel 199; panels such as indicated at 201 inFIG. 3 inclining inwardly from the rear ends of panels 196 and generallyparallel to channel portions 44; and triangular panels such as indicatedat 202 which incline rearwardly, inwardly and upwardly from the upperside portions 192. The front panel 199 is generally of the same width asthe tank 120.

What is claimed is:

1. A high-clearance agricultural vehicle comprising a main frameextending longitudinally from the front to the rear of the upper portionof said vehicle, said main frame having a rear portion, intermediateportion and forward portion, said main frame being defined by a pair oflaterally spaced apart, longitudinally extendingside members as theprimary structural members, said side members being generallysymmetrically formed and laterally spaced apart relative to a verticallyand longitudinally extending center plane of said vehicle, the portionsof said-side members defining said rear portion being generally paralleland spaced apart by a first distance, the portions of said side membersdefining said intermediate portion inclining laterally outwardly andforwardly, and the portions of said side members defining said forwardportion being generally parallel and spaced apart a second and greaterdistance to provide a cockpit for the operator therebetween, a pair ofrear wheels, means for mounting said rear wheels extending outwardly anddownwardly from each side of the rear portion of said main frame, afront wheel, a trunnion support for journal mounting said front wheel, asteering column for connecting said trunnion support to the forwardportion of said main frame for pivotal movement about a steeringaxislying generally in said center plane, a tank having a widthgenerally equal to said first distance depending from the rear portionof said main frame and disposed axially between said rear wheels, anengine supported under the forward portion of said main frame, an axleassembly supported on the rear portion of said main frame, transmissionmeans supported on said main frame and drivingly connected said engineand said axle assembly, means for drivingly connecting said axleassembly to said rear wheels, enclosure means depending from the forwardportion of said main frame to enclose said engine, said enclosure meansincluding opposing side wall means having upper side portions extendingdownwardly from said forward portion to a point above said engine andlower side portions extending respectively downwardly from said upperside portions to a point below said engine, the distancebetween saidlower side portions being generally equal to said first distance.

2. The vehicle of claim 1 in which said side wall means extend forwardlyof said steering column to provide, above said front wheel and forwardlyof said cockpit, a chamber in communication with the portion of saidenclosure means enclosing said engine, and including front wall meansfor said chamber disposed between said side wall means and constructedto permit air flow therethrough, radiator means disposed in said chamberfor cooling said engine, and fan means disposed in said chamber formoving air through said radiator means.

3. The vehicle of claim 2 I in which said side wall means provideventilation openings adjacent said engine, said fan means being disposedto draw air into said enclosure means through said ventilation openingsand to move it through said radiator and out through said front wallmeans.

4. The vehicle of claim 3 in which said engine has a crankshaft andincluding means for drivingly connecting said fan means to said enginecomprising jack shaft means journal mounted in said enclosure meansabove the crankshaft of said engine and extending forwardly into saidchamber, pulley and belt means for drivingly connecting the rear end ofsaid jack shaft means to the crankshaft of said engine and second pulleyand belt means for drivingly connecting the forward end of sai jackshaft means to said fan means.

5. The vehicle of claim 4 in which the axis of the crankshaft liesgenerally in said center plane and the axis of said jack shaft means isgenerally parallel to and spaced apart from said center plane to'passsaid steering column.

6. The vehicle of claim 1 in which said engine is a water-cooled engineand including means providing a chamber above said front wheel andforwardly of said cockpit, radiator means disposed in said chamber forcooling said engine, and fan means disposed in said chamber for movingair through said radiator means.

7. The vehicle of claim 1 in which each said means for journal mountingone of said rear wheels includes a yoke providing a base and laterallyspaced apart flanges extending downwardly from said base, said rearwheel being disposed between said flanges, a trunnion carried by saidflanges for journal mounting said wheel, rigid support arm meansextending outwardly and downwardly from said rear portion, mountingbracket means carried by the distal end of said arm means, and means forconnecting said yoke base to said mounting bracket means for selectivelyadjustable lateral movement. 7

8. The vehicle of claim 7 in which said mounting bracket means includesa laterally and horizontally ex tending plate providing a downwardlyfacing surface, said yoke base providing a horizontally extendingupwardly facing surface engaging said downwardly facing surface, saidconnecting means including fastening elements penetrating said surfaces.

9. A high-clearance agricultural vehicle comprising a main frameextending generally horizontally and longitudinally from the front tothe rear of the upper portion of said vehicle, said main frame having arear portion, intermediate. portion and forward portion, said main framebeing defined by a pair of laterally spaced apart, longitudinallyextending channel members as the primary structural members, saidchannel members being allochirally formed and arranged to have generallyvertically extending vertical webs and upper and lower extendingflanges, the portions of said channel members defining said rear portionbeing generally parallel and spaced apart by a first distance, theportions of said channel members defining said intermediate portioninclining laterally outwardly and forwardly, and the portions of saidchannel members defining said forward portion being generally paralleland spaced apart a second and greater distance to provide a cockpit forthe operator therebetween, rear drive wheels disposed on opposite sidesof said rear portion, means for mounting each said rear wheel extendingoutwardly and downwardly from the adjacent side of said rear portion, a

front wheel, a trunnion support for journal mounting said front wheel, asteering column for connecting said trunnion support to the forwardportion of said main frame for pivotal movement about a steering axis,an engine supported under the forward portion of said main frame to beunder said cockpit, enclosure means depending from said forward portionto enclose said engine, said enclosure means including opposing sidewall means having lower side portions on opposite sides of said engine,the distance between said lower side portions being generally equal tosaid first distance.

10. The vehicle of claim 9 in which said opposing side wall meansinclude upper side portions extending respectively upwardly andoutwardly from the upper edges of said lower side portions to saidportions of said channel members defining said forward portion.

11. The vehicle of claim 10 in which said upper side portions includerespectively forward portions inclining inwardly and forwardly to awidth generally equal to said first distance and rear portions inclininginwardly and rearwardly to said width.

12. A high-clearance agricultural vehicle comprising a main frameextending generally horizontally and longitudinally from the front tothe rear of the upper portion of said vehicle, said main frame having arear portion, intermediate portion and forward portion, said main framebeing defined by frame members proportioned and designed such thatsaidrear portion is of a first lateral width and said forward portion is ofa second and greater lateral width to provide a cockpit for the operatortherebetween, a tank centrally supported under said rear portion, saidtank having a Width generally equal to said first width, rear drivewheels disposed on opposite sides of said tank, means for mounting eachsaid rear wheel extending outwardly and downwardly from the adjacentside of said rear portion, a front wheel, a trunnion support for journalmounting said front wheel, a steering column for connecting saidtrunnion support to the forward portion of said main frame for pivotalmovement about a steering axis, an engine supported under the forwardportion of said frame to be under said cockpit, enclosure meansdepending from said forward portion to enclose said engine, saidenclosure means including opposing side wall means having lower sideportions on opposite sides of said engine, the distance between saidlower side portions being generally equal to said first width.

1. A high-clearance agricultural vehicle comprising a main frameextending longitudinally from the front to the rear of the upper portionof said vehicle, said main frame having a rear portion, intermediateportion and forward portion, said main frame being defined by a pair oflaterally spaced apart, longitudinally extending side members as theprimary structural members, said side members being generallysymmetrically formed and laterally spaced apart relative to a verticallyand longitudinally extending center plane of said vehicle, the portionsof said side members defining said rear portion being generally paralleland spaced apart by a first distance, the portions of said side membersdefining said intermediate portion inclining laterally outwardly andforwardly, and the portions of said side members defining said forwardportion being generally parallel and spaced apart a second and greaterdistance to provide a cockpit for the operator therebetween, a pair ofrear wheels, means for mounting said rear wheels extending outwardly anddownwardly from Each side of the rear portion of said main frame, afront wheel, a trunnion support for journal mounting said front wheel, asteering column for connecting said trunnion support to the forwardportion of said main frame for pivotal movement about a steering axislying generally in said center plane, a tank having a width generallyequal to said first distance depending from the rear portion of saidmain frame and disposed axially between said rear wheels, an enginesupported under the forward portion of said main frame, an axle assemblysupported on the rear portion of said main frame, transmission meanssupported on said main frame and drivingly connected said engine andsaid axle assembly, means for drivingly connecting said axle assembly tosaid rear wheels, enclosure means depending from the forward portion ofsaid main frame to enclose said engine, said enclosure means includingopposing side wall means having upper side portions extending downwardlyfrom said forward portion to a point above said engine and lower sideportions extending respectively downwardly from said upper side portionsto a point below said engine, the distance between said lower sideportions being generally equal to said first distance.
 2. The vehicle ofclaim 1 in which said side wall means extend forwardly of said steeringcolumn to provide, above said front wheel and forwardly of said cockpit,a chamber in communication with the portion of said enclosure meansenclosing said engine, and including front wall means for said chamberdisposed between said side wall means and constructed to permit air flowtherethrough, radiator means disposed in said chamber for cooling saidengine, and fan means disposed in said chamber for moving air throughsaid radiator means.
 3. The vehicle of claim 2 in which said side wallmeans provide ventilation openings adjacent said engine, said fan meansbeing disposed to draw air into said enclosure means through saidventilation openings and to move it through said radiator and outthrough said front wall means.
 4. The vehicle of claim 3 in which saidengine has a crankshaft and including means for drivingly connectingsaid fan means to said engine comprising jack shaft means journalmounted in said enclosure means above the crankshaft of said engine andextending forwardly into said chamber, pulley and belt means fordrivingly connecting the rear end of said jack shaft means to thecrankshaft of said engine and second pulley and belt means for drivinglyconnecting the forward end of said jack shaft means to said fan means.5. The vehicle of claim 4 in which the axis of the crankshaft liesgenerally in said center plane and the axis of said jack shaft means isgenerally parallel to and spaced apart from said center plane to passsaid steering column.
 6. The vehicle of claim 1 in which said engine isa water-cooled engine and including means providing a chamber above saidfront wheel and forwardly of said cockpit, radiator means disposed insaid chamber for cooling said engine, and fan means disposed in saidchamber for moving air through said radiator means.
 7. The vehicle ofclaim 1 in which each said means for journal mounting one of said rearwheels includes a yoke providing a base and laterally spaced apartflanges extending downwardly from said base, said rear wheel beingdisposed between said flanges, a trunnion carried by said flanges forjournal mounting said wheel, rigid support arm means extending outwardlyand downwardly from said rear portion, mounting bracket means carried bythe distal end of said arm means, and means for connecting said yokebase to said mounting bracket means for selectively adjustable lateralmovement.
 8. The vehicle of claim 7 in which said mounting bracket meansincludes a laterally and horizontally extending plate providing adownwardly facing surface, said yoke base providing a horizontallyextending upwardly facing surface engaging said downwardly facingsurface, said connecting means including fastening elEments penetratingsaid surfaces.
 9. A high-clearance agricultural vehicle comprising amain frame extending generally horizontally and longitudinally from thefront to the rear of the upper portion of said vehicle, said main framehaving a rear portion, intermediate portion and forward portion, saidmain frame being defined by a pair of laterally spaced apart,longitudinally extending channel members as the primary structuralmembers, said channel members being allochirally formed and arranged tohave generally vertically extending vertical webs and upper and lowerextending flanges, the portions of said channel members defining saidrear portion being generally parallel and spaced apart by a firstdistance, the portions of said channel members defining saidintermediate portion inclining laterally outwardly and forwardly, andthe portions of said channel members defining said forward portion beinggenerally parallel and spaced apart a second and greater distance toprovide a cockpit for the operator therebetween, rear drive wheelsdisposed on opposite sides of said rear portion, means for mounting eachsaid rear wheel extending outwardly and downwardly from the adjacentside of said rear portion, a front wheel, a trunnion support for journalmounting said front wheel, a steering column for connecting saidtrunnion support to the forward portion of said main frame for pivotalmovement about a steering axis, an engine supported under the forwardportion of said main frame to be under said cockpit, enclosure meansdepending from said forward portion to enclose said engine, saidenclosure means including opposing side wall means having lower sideportions on opposite sides of said engine, the distance between saidlower side portions being generally equal to said first distance. 10.The vehicle of claim 9 in which said opposing side wall means includeupper side portions extending respectively upwardly and outwardly fromthe upper edges of said lower side portions to said portions of saidchannel members defining said forward portion.
 11. The vehicle of claim10 in which said upper side portions include respectively forwardportions inclining inwardly and forwardly to a width generally equal tosaid first distance and rear portions inclining inwardly and rearwardlyto said width.
 12. A high-clearance agricultural vehicle comprising amain frame extending generally horizontally and longitudinally from thefront to the rear of the upper portion of said vehicle, said main framehaving a rear portion, intermediate portion and forward portion, saidmain frame being defined by frame members proportioned and designed suchthat said rear portion is of a first lateral width and said forwardportion is of a second and greater lateral width to provide a cockpitfor the operator therebetween, a tank centrally supported under saidrear portion, said tank having a width generally equal to said firstwidth, rear drive wheels disposed on opposite sides of said tank, meansfor mounting each said rear wheel extending outwardly and downwardlyfrom the adjacent side of said rear portion, a front wheel, a trunnionsupport for journal mounting said front wheel, a steering column forconnecting said trunnion support to the forward portion of said mainframe for pivotal movement about a steering axis, an engine supportedunder the forward portion of said frame to be under said cockpit,enclosure means depending from said forward portion to enclose saidengine, said enclosure means including opposing side wall means havinglower side portions on opposite sides of said engine, the distancebetween said lower side portions being generally equal to said firstwidth.